 Chemistry CIE iGCSE:
Calculations 1c

For Double and Triple sciences

Grab a calculator and a copy of the periodic table

(This test has only 10 questions, but may take 15 - 20 mins).

This test mainly covers calculations involving solutions

1. The correct formula for the concentration of a solution in mol/dm3 is..
• A.   concentration = number of moles x volume in cm3
• B.   concentration = number of moles x volume in dm3
• C.   concentration = number of moles ÷ volume in cm3
• D.   concentration = number of moles ÷ volume in dm3
2. 100cm3 of a sodium hydroxide solution was prepared by dissolving 20g of sodium hydroxide, NaOH, in water.

What is the concentration of this solution in g/dm3?

• A.   0.2 g/dm3
• B.   5 g/dm3
• C.   20 g/dm3
• D.   200 g/dm3
3. Which solution contains the greatest number of moles?
• A.   20 cm3 of 2.0 mol/dm3 hydrochloric acid
• B.   40 cm3 of 1.0 mol/dm3 hydrochloric acid
• C.   60 cm3 of 1.0 mol/dm3 sodium hydroxide
• D.   80 cm3 of 0.5 mol/dm3 sodium hydroxide
4. 1.0dm3 of ethanoic acid solution, CH3COOH, contains 6.0 g of ethanoic acid

[Mr value of CH3COOH = 60].
The concentration of the ethanoic acid solution, in mol/dm3, is..

• A.   0.1
• B.   0.6
• C.   1.0
• D.   10
5. Sodium hydroxide solution can be neutralized using dilute ethanoic acid. The equation for the reaction is:

NaOH(aq) + CH3COOH(aq)  CH3COONa(aq) + H2O(l)

Calculate the volume of 0.200 mol/dm3 ethanoic acid needed to exactly neutralize 0.0025 moles of sodium hydroxide solution.

• A.   0.0125 cm3
• B.   1.25 cm3
• C.   12.5 cm3
• D.   12.5 dm3
6. 0.30 moles of barium chloride solution was added to 0.20 moles of magnesium sulfate solution in the following precipitation reaction:

BaCl2(aq) + MgSO4(aq)  BaSO4(s) + MgCl2(aq)

How many moles of barium sulfate, BaSO4, would be produced?

• A.   0.20
• B.   0.25
• C.   0.30
• D.   0.50

Q7-10:
A student used a titration method to find the concentration of a solution of oxalic acid, H2C2O4. The equation for the reaction is:

2NaOH(aq) + H2C2O4(aq)  Na2C2O4(aq) + 2H2O(l)

She obtained the following results:

 Volume of sodium hydroxide solution in conical flask 25.0 cm3 Concentration of sodium hydroxide solution 0.120 mol/dm3 Average volume of oxalic acid solution added 18.30 cm3

7. Calculate the amount, in moles, of sodium hydroxide used.
• A.   3.00
• B.   0.00300
• C.   2.20
• D.   0.00220
8. Calculate the concentration, in mol/dm3, of the oxalic acid.
• A.   0.328
• B.   0.164
• C.   0.0820
• D.   0.0440
9. The piece of apparatus used to measure the volume of sodium hydroxide is a .
10. The piece of apparatus used to measure the volume of oxalic acid is a .